[Canadian Man]

If you are using straight calgary water you will be adding some calcium and buffer to your tank. The problem arises when you have any stony coral because they soak up the calcium and alk very fast. If you add kalk the proper way (as mentioned in the article) you should not experience any problems with white precipitate in your tank. The precipitate is usually experienced when adding a single additive like just calcium or buffer as you are throwing out the ballance. when you use a ballanced sollustion like kalk you are adding both calcium and buffer at the same time in the right ammounts to eachother.
Phew.... that was a mouthful
jonathan